// SPDX-License-Identifier: GPL-2.0 /* * Texas Instruments K3 RTC driver * * Copyright (C) 2021-2022 Texas Instruments Incorporated - https://www.ti.com/ */ #include <linux/clk.h> #include <linux/delay.h> #include <linux/mod_devicetable.h> #include <linux/module.h> #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/sys_soc.h> #include <linux/property.h> #include <linux/regmap.h> #include <linux/rtc.h> /* Registers */ #define REG_K3RTC_S_CNT_LSW 0x08 #define REG_K3RTC_S_CNT_MSW 0x0c #define REG_K3RTC_COMP 0x10 #define REG_K3RTC_ON_OFF_S_CNT_LSW 0x20 #define REG_K3RTC_ON_OFF_S_CNT_MSW 0x24 #define REG_K3RTC_SCRATCH0 0x30 #define REG_K3RTC_SCRATCH7 0x4c #define REG_K3RTC_GENERAL_CTL 0x50 #define REG_K3RTC_IRQSTATUS_RAW_SYS 0x54 #define REG_K3RTC_IRQSTATUS_SYS 0x58 #define REG_K3RTC_IRQENABLE_SET_SYS 0x5c #define REG_K3RTC_IRQENABLE_CLR_SYS 0x60 #define REG_K3RTC_SYNCPEND 0x68 #define REG_K3RTC_KICK0 0x70 #define REG_K3RTC_KICK1 0x74 /* Freeze when lsw is read and unfreeze when msw is read */ #define K3RTC_CNT_FMODE_S_CNT_VALUE (0x2 << 24) /* Magic values for lock/unlock */ #define K3RTC_KICK0_UNLOCK_VALUE 0x83e70b13 #define K3RTC_KICK1_UNLOCK_VALUE 0x95a4f1e0 /* Multiplier for ppb conversions */ #define K3RTC_PPB_MULT (1000000000LL) /* Min and max values supported with 'offset' interface (swapped sign) */ #define K3RTC_MIN_OFFSET (-277761) #define K3RTC_MAX_OFFSET (277778) static const struct regmap_config ti_k3_rtc_regmap_config = { .name = "peripheral-registers", .reg_bits = 32, .val_bits = 32, .reg_stride = 4, .max_register = REG_K3RTC_KICK1, }; enum ti_k3_rtc_fields { K3RTC_KICK0, K3RTC_KICK1, K3RTC_S_CNT_LSW, K3RTC_S_CNT_MSW, K3RTC_O32K_OSC_DEP_EN, K3RTC_UNLOCK, K3RTC_CNT_FMODE, K3RTC_PEND, K3RTC_RELOAD_FROM_BBD, K3RTC_COMP, K3RTC_ALM_S_CNT_LSW, K3RTC_ALM_S_CNT_MSW, K3RTC_IRQ_STATUS_RAW, K3RTC_IRQ_STATUS, K3RTC_IRQ_ENABLE_SET, K3RTC_IRQ_ENABLE_CLR, K3RTC_IRQ_STATUS_ALT, K3RTC_IRQ_ENABLE_CLR_ALT, K3_RTC_MAX_FIELDS }; static const struct reg_field ti_rtc_reg_fields[] = { [K3RTC_KICK0] = REG_FIELD(REG_K3RTC_KICK0, 0, 31), [K3RTC_KICK1] = REG_FIELD(REG_K3RTC_KICK1, 0, 31), [K3RTC_S_CNT_LSW] = REG_FIELD(REG_K3RTC_S_CNT_LSW, 0, 31), [K3RTC_S_CNT_MSW] = REG_FIELD(REG_K3RTC_S_CNT_MSW, 0, 15), [K3RTC_O32K_OSC_DEP_EN] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 21, 21), [K3RTC_UNLOCK] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 23, 23), [K3RTC_CNT_FMODE] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 24, 25), [K3RTC_PEND] = REG_FIELD(REG_K3RTC_SYNCPEND, 0, 1), [K3RTC_RELOAD_FROM_BBD] = REG_FIELD(REG_K3RTC_SYNCPEND, 31, 31), [K3RTC_COMP] = REG_FIELD(REG_K3RTC_COMP, 0, 31), /* We use on to off as alarm trigger */ [K3RTC_ALM_S_CNT_LSW] = REG_FIELD(REG_K3RTC_ON_OFF_S_CNT_LSW, 0, 31), [K3RTC_ALM_S_CNT_MSW] = REG_FIELD(REG_K3RTC_ON_OFF_S_CNT_MSW, 0, 15), [K3RTC_IRQ_STATUS_RAW] = REG_FIELD(REG_K3RTC_IRQSTATUS_RAW_SYS, 0, 0), [K3RTC_IRQ_STATUS] = REG_FIELD(REG_K3RTC_IRQSTATUS_SYS, 0, 0), [K3RTC_IRQ_ENABLE_SET] = REG_FIELD(REG_K3RTC_IRQENABLE_SET_SYS, 0, 0), [K3RTC_IRQ_ENABLE_CLR] = REG_FIELD(REG_K3RTC_IRQENABLE_CLR_SYS, 0, 0), /* Off to on is alternate */ [K3RTC_IRQ_STATUS_ALT] = REG_FIELD(REG_K3RTC_IRQSTATUS_SYS, 1, 1), [K3RTC_IRQ_ENABLE_CLR_ALT] = REG_FIELD(REG_K3RTC_IRQENABLE_CLR_SYS, 1, 1), }; /** * struct ti_k3_rtc - Private data for ti-k3-rtc * @irq: IRQ * @sync_timeout_us: data sync timeout period in uSec * @rate_32k: 32k clock rate in Hz * @rtc_dev: rtc device * @regmap: rtc mmio regmap * @r_fields: rtc register fields */ struct ti_k3_rtc { unsigned int irq; u32 sync_timeout_us; unsigned long rate_32k; struct rtc_device *rtc_dev; struct regmap *regmap; struct regmap_field *r_fields[K3_RTC_MAX_FIELDS]; }; static int k3rtc_field_read(struct ti_k3_rtc *priv, enum ti_k3_rtc_fields f) { int ret; int val; ret = regmap_field_read(priv->r_fields[f], &val); /* * We shouldn't be seeing regmap fail on us for mmio reads * This is possible if clock context fails, but that isn't the case for us */ if (WARN_ON_ONCE(ret)) return ret; return val; } static void k3rtc_field_write(struct ti_k3_rtc *priv, enum ti_k3_rtc_fields f, u32 val) { regmap_field_write(priv->r_fields[f], val); } /** * k3rtc_fence - Ensure a register sync took place between the two domains * @priv: pointer to priv data * * Return: 0 if the sync took place, else returns -ETIMEDOUT */ static int k3rtc_fence(struct ti_k3_rtc *priv) { int ret; ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_PEND], ret, !ret, 2, priv->sync_timeout_us); return ret; } static inline int k3rtc_check_unlocked(struct ti_k3_rtc *priv) { int ret; ret = k3rtc_field_read(priv, K3RTC_UNLOCK); if (ret < 0) return ret; return (ret) ? 0 : 1; } static int k3rtc_unlock_rtc(struct ti_k3_rtc *priv) { int ret; ret = k3rtc_check_unlocked(priv); if (!ret) return ret; k3rtc_field_write(priv, K3RTC_KICK0, K3RTC_KICK0_UNLOCK_VALUE); k3rtc_field_write(priv, K3RTC_KICK1, K3RTC_KICK1_UNLOCK_VALUE); /* Skip fence since we are going to check the unlock bit as fence */ ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_UNLOCK], ret, ret, 2, priv->sync_timeout_us); return ret; } /* * This is the list of SoCs affected by TI's i2327 errata causing the RTC * state-machine to break if not unlocked fast enough during boot. These * SoCs must have the bootloader unlock this device very early in the * boot-flow before we (Linux) can use this device. */ static const struct soc_device_attribute has_erratum_i2327[] = { { .family = "AM62X", .revision = "SR1.0" }, { /* sentinel */ } }; static int k3rtc_configure(struct device *dev) { int ret; struct ti_k3_rtc *priv = dev_get_drvdata(dev); /* * HWBUG: The compare state machine is broken if the RTC module * is NOT unlocked in under one second of boot - which is pretty long * time from the perspective of Linux driver (module load, u-boot * shell all can take much longer than this. * * In such occurrence, it is assumed that the RTC module is unusable */ if (soc_device_match(has_erratum_i2327)) { ret = k3rtc_check_unlocked(priv); /* If there is an error OR if we are locked, return error */ if (ret) { dev_err(dev, HW_ERR "Erratum i2327 unlock QUIRK! Cannot operate!!\n"); return -EFAULT; } } else { /* May need to explicitly unlock first time */ ret = k3rtc_unlock_rtc(priv); if (ret) { dev_err(dev, "Failed to unlock(%d)!\n", ret); return ret; } } /* Enable Shadow register sync on 32k clock boundary */ k3rtc_field_write(priv, K3RTC_O32K_OSC_DEP_EN, 0x1); /* * Wait at least clock sync time before proceeding further programming. * This ensures that the 32k based sync is active. */ usleep_range(priv->sync_timeout_us, priv->sync_timeout_us + 5); /* We need to ensure fence here to make sure sync here */ ret = k3rtc_fence(priv); if (ret) { dev_err(dev, "Failed fence osc_dep enable(%d) - is 32k clk working?!\n", ret); return ret; } /* * FMODE setting: Reading lower seconds will freeze value on higher * seconds. This also implies that we must *ALWAYS* read lower seconds * prior to reading higher seconds */ k3rtc_field_write(priv, K3RTC_CNT_FMODE, K3RTC_CNT_FMODE_S_CNT_VALUE); /* Clear any spurious IRQ sources if any */ k3rtc_field_write(priv, K3RTC_IRQ_STATUS_ALT, 0x1); k3rtc_field_write(priv, K3RTC_IRQ_STATUS, 0x1); /* Disable all IRQs */ k3rtc_field_write(priv, K3RTC_IRQ_ENABLE_CLR_ALT, 0x1); k3rtc_field_write(priv, K3RTC_IRQ_ENABLE_CLR, 0x1); /* And.. Let us Sync the writes in */ return k3rtc_fence(priv); } static int ti_k3_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct ti_k3_rtc *priv = dev_get_drvdata(dev); u32 seconds_lo, seconds_hi; seconds_lo = k3rtc_field_read(priv, K3RTC_S_CNT_LSW); seconds_hi = k3rtc_field_read(priv, K3RTC_S_CNT_MSW); rtc_time64_to_tm((((time64_t)seconds_hi) << 32) | (time64_t)seconds_lo, tm); return 0; } static int ti_k3_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct ti_k3_rtc *priv = dev_get_drvdata(dev); time64_t seconds; seconds = rtc_tm_to_time64(tm); /* * Read operation on LSW will freeze the RTC, so to update * the time, we cannot use field operations. Just write since the * reserved bits are ignored. */ regmap_write(priv->regmap, REG_K3RTC_S_CNT_LSW, seconds); regmap_write(priv->regmap, REG_K3RTC_S_CNT_MSW, seconds >> 32); return k3rtc_fence(priv); } static int ti_k3_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) { struct ti_k3_rtc *priv = dev_get_drvdata(dev); u32 reg; u32 offset = enabled ? K3RTC_IRQ_ENABLE_SET : K3RTC_IRQ_ENABLE_CLR; reg = k3rtc_field_read(priv, K3RTC_IRQ_ENABLE_SET); if ((enabled && reg) || (!enabled && !reg)) return 0; k3rtc_field_write(priv, offset, 0x1); /* * Ensure the write sync is through - NOTE: it should be OK to have * ISR to fire as we are checking sync (which should be done in a 32k * cycle or so). */ return k3rtc_fence(priv); } static int ti_k3_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) { struct ti_k3_rtc *priv = dev_get_drvdata(dev); u32 seconds_lo, seconds_hi; seconds_lo = k3rtc_field_read(priv, K3RTC_ALM_S_CNT_LSW); seconds_hi = k3rtc_field_read(priv, K3RTC_ALM_S_CNT_MSW); rtc_time64_to_tm((((time64_t)seconds_hi) << 32) | (time64_t)seconds_lo, &alarm->time); alarm->enabled = k3rtc_field_read(priv, K3RTC_IRQ_ENABLE_SET); return 0; } static int ti_k3_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) { struct ti_k3_rtc *priv = dev_get_drvdata(dev); time64_t seconds; int ret; seconds = rtc_tm_to_time64(&alarm->time); k3rtc_field_write(priv, K3RTC_ALM_S_CNT_LSW, seconds); k3rtc_field_write(priv, K3RTC_ALM_S_CNT_MSW, (seconds >> 32)); /* Make sure the alarm time is synced in */ ret = k3rtc_fence(priv); if (ret) { dev_err(dev, "Failed to fence(%d)! Potential config issue?\n", ret); return ret; } /* Alarm IRQ enable will do a sync */ return ti_k3_rtc_alarm_irq_enable(dev, alarm->enabled); } static int ti_k3_rtc_read_offset(struct device *dev, long *offset) { struct ti_k3_rtc *priv = dev_get_drvdata(dev); u32 ticks_per_hr = priv->rate_32k * 3600; int comp; s64 tmp; comp = k3rtc_field_read(priv, K3RTC_COMP); /* Convert from RTC calibration register format to ppb format */ tmp = comp * (s64)K3RTC_PPB_MULT; if (tmp < 0) tmp -= ticks_per_hr / 2LL; else tmp += ticks_per_hr / 2LL; tmp = div_s64(tmp, ticks_per_hr); /* Offset value operates in negative way, so swap sign */ *offset = (long)-tmp; return 0; } static int ti_k3_rtc_set_offset(struct device *dev, long offset) { struct ti_k3_rtc *priv = dev_get_drvdata(dev); u32 ticks_per_hr = priv->rate_32k * 3600; int comp; s64 tmp; /* Make sure offset value is within supported range */ if (offset < K3RTC_MIN_OFFSET || offset > K3RTC_MAX_OFFSET) return -ERANGE; /* Convert from ppb format to RTC calibration register format */ tmp = offset * (s64)ticks_per_hr; if (tmp < 0) tmp -= K3RTC_PPB_MULT / 2LL; else tmp += K3RTC_PPB_MULT / 2LL; tmp = div_s64(tmp, K3RTC_PPB_MULT); /* Offset value operates in negative way, so swap sign */ comp = (int)-tmp; k3rtc_field_write(priv, K3RTC_COMP, comp); return k3rtc_fence(priv); } static irqreturn_t ti_k3_rtc_interrupt(s32 irq, void *dev_id) { struct device *dev = dev_id; struct ti_k3_rtc *priv = dev_get_drvdata(dev); u32 reg; int ret; /* * IRQ assertion can be very fast, however, the IRQ Status clear * de-assert depends on 32k clock edge in the 32k domain * If we clear the status prior to the first 32k clock edge, * the status bit is cleared, but the IRQ stays re-asserted. * * To prevent this condition, we need to wait for clock sync time. * We can either do that by polling the 32k observability signal for * a toggle OR we could just sleep and let the processor do other * stuff. */ usleep_range(priv->sync_timeout_us, priv->sync_timeout_us + 2); /* Lets make sure that this is a valid interrupt */ reg = k3rtc_field_read(priv, K3RTC_IRQ_STATUS); if (!reg) { u32 raw = k3rtc_field_read(priv, K3RTC_IRQ_STATUS_RAW); dev_err(dev, HW_ERR "Erratum i2327/IRQ trig: status: 0x%08x / 0x%08x\n", reg, raw); return IRQ_NONE; } /* * Write 1 to clear status reg * We cannot use a field operation here due to a potential race between * 32k domain and vbus domain. */ regmap_write(priv->regmap, REG_K3RTC_IRQSTATUS_SYS, 0x1); /* Sync the write in */ ret = k3rtc_fence(priv); if (ret) { dev_err(dev, "Failed to fence irq status clr(%d)!\n", ret); return IRQ_NONE; } /* * Force the 32k status to be reloaded back in to ensure status is * reflected back correctly. */ k3rtc_field_write(priv, K3RTC_RELOAD_FROM_BBD, 0x1); /* Ensure the write sync is through */ ret = k3rtc_fence(priv); if (ret) { dev_err(dev, "Failed to fence reload from bbd(%d)!\n", ret); return IRQ_NONE; } /* Now we ensure that the status bit is cleared */ ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_IRQ_STATUS], ret, !ret, 2, priv->sync_timeout_us); if (ret) { dev_err(dev, "Time out waiting for status clear\n"); return IRQ_NONE; } /* Notify RTC core on event */ rtc_update_irq(priv->rtc_dev, 1, RTC_IRQF | RTC_AF); return IRQ_HANDLED; } static const struct rtc_class_ops ti_k3_rtc_ops = { .read_time = ti_k3_rtc_read_time, .set_time = ti_k3_rtc_set_time, .read_alarm = ti_k3_rtc_read_alarm, .set_alarm = ti_k3_rtc_set_alarm, .read_offset = ti_k3_rtc_read_offset, .set_offset = ti_k3_rtc_set_offset, .alarm_irq_enable = ti_k3_rtc_alarm_irq_enable, }; static int ti_k3_rtc_scratch_read(void *priv_data, unsigned int offset, void *val, size_t bytes) { struct ti_k3_rtc *priv = (struct ti_k3_rtc *)priv_data; return regmap_bulk_read(priv->regmap, REG_K3RTC_SCRATCH0 + offset, val, bytes / 4); } static int ti_k3_rtc_scratch_write(void *priv_data, unsigned int offset, void *val, size_t bytes) { struct ti_k3_rtc *priv = (struct ti_k3_rtc *)priv_data; int ret; ret = regmap_bulk_write(priv->regmap, REG_K3RTC_SCRATCH0 + offset, val, bytes / 4); if (ret) return ret; return k3rtc_fence(priv); } static struct nvmem_config ti_k3_rtc_nvmem_config = { .name = "ti_k3_rtc_scratch", .word_size = 4, .stride = 4, .size = REG_K3RTC_SCRATCH7 - REG_K3RTC_SCRATCH0 + 4, .reg_read = ti_k3_rtc_scratch_read, .reg_write = ti_k3_rtc_scratch_write, }; static int k3rtc_get_32kclk(struct device *dev, struct ti_k3_rtc *priv) { struct clk *clk; clk = devm_clk_get_enabled(dev, "osc32k"); if (IS_ERR(clk)) return PTR_ERR(clk); priv->rate_32k = clk_get_rate(clk); /* Make sure we are exact 32k clock. Else, try to compensate delay */ if (priv->rate_32k != 32768) dev_warn(dev, "Clock rate %ld is not 32768! Could misbehave!\n", priv->rate_32k); /* * Sync timeout should be two 32k clk sync cycles = ~61uS. We double * it to comprehend intermediate bus segment and cpu frequency * deltas */ priv->sync_timeout_us = (u32)(DIV_ROUND_UP_ULL(1000000, priv->rate_32k) * 4); return 0; } static int k3rtc_get_vbusclk(struct device *dev, struct ti_k3_rtc *priv) { struct clk *clk; /* Note: VBUS isn't a context clock, it is needed for hardware operation */ clk = devm_clk_get_enabled(dev, "vbus"); if (IS_ERR(clk)) return PTR_ERR(clk); return 0; } static int ti_k3_rtc_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct ti_k3_rtc *priv; void __iomem *rtc_base; int ret; priv = devm_kzalloc(dev, sizeof(struct ti_k3_rtc), GFP_KERNEL); if (!priv) return -ENOMEM; rtc_base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(rtc_base)) return PTR_ERR(rtc_base); priv->regmap = devm_regmap_init_mmio(dev, rtc_base, &ti_k3_rtc_regmap_config); if (IS_ERR(priv->regmap)) return PTR_ERR(priv->regmap); ret = devm_regmap_field_bulk_alloc(dev, priv->regmap, priv->r_fields, ti_rtc_reg_fields, K3_RTC_MAX_FIELDS); if (ret) return ret; ret = k3rtc_get_32kclk(dev, priv); if (ret) return ret; ret = k3rtc_get_vbusclk(dev, priv); if (ret) return ret; ret = platform_get_irq(pdev, 0); if (ret < 0) return ret; priv->irq = (unsigned int)ret; priv->rtc_dev = devm_rtc_allocate_device(dev); if (IS_ERR(priv->rtc_dev)) return PTR_ERR(priv->rtc_dev); priv->rtc_dev->ops = &ti_k3_rtc_ops; priv->rtc_dev->range_max = (1ULL << 48) - 1; /* 48Bit seconds */ ti_k3_rtc_nvmem_config.priv = priv; ret = devm_request_threaded_irq(dev, priv->irq, NULL, ti_k3_rtc_interrupt, IRQF_TRIGGER_HIGH | IRQF_ONESHOT, dev_name(dev), dev); if (ret) { dev_err(dev, "Could not request IRQ: %d\n", ret); return ret; } platform_set_drvdata(pdev, priv); ret = k3rtc_configure(dev); if (ret) return ret; if (device_property_present(dev, "wakeup-source")) device_init_wakeup(dev, true); else device_set_wakeup_capable(dev, true); ret = devm_rtc_register_device(priv->rtc_dev); if (ret) return ret; return devm_rtc_nvmem_register(priv->rtc_dev, &ti_k3_rtc_nvmem_config); } static const struct of_device_id ti_k3_rtc_of_match_table[] = { {.compatible = "ti,am62-rtc" }, {} }; MODULE_DEVICE_TABLE(of, ti_k3_rtc_of_match_table); static int __maybe_unused ti_k3_rtc_suspend(struct device *dev) { struct ti_k3_rtc *priv = dev_get_drvdata(dev); if (device_may_wakeup(dev)) enable_irq_wake(priv->irq); return 0; } static int __maybe_unused ti_k3_rtc_resume(struct device *dev) { struct ti_k3_rtc *priv = dev_get_drvdata(dev); if (device_may_wakeup(dev)) disable_irq_wake(priv->irq); return 0; } static SIMPLE_DEV_PM_OPS(ti_k3_rtc_pm_ops, ti_k3_rtc_suspend, ti_k3_rtc_resume); static struct platform_driver ti_k3_rtc_driver = { .probe = ti_k3_rtc_probe, .driver = { .name = "rtc-ti-k3", .of_match_table = ti_k3_rtc_of_match_table, .pm = &ti_k3_rtc_pm_ops, }, }; module_platform_driver(ti_k3_rtc_driver); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("TI K3 RTC driver"); MODULE_AUTHOR("Nishanth Menon");